Do you have a Cingular BlackBerry and like to chat on Yahoo?Pinstacker Stack Pro N8DBB recently complied a How To Guide for Cingular BlackBerrys to get Yahoo IM from other posts.
The problem is that Cingular does not have the service book required for Yahoo IM to work on your BlackBerry.
If you have an unlocked BlackBerry and a friend with another provider's SIM card you could always pop that into your BlackBerry and get the service books.
If not there are a few steps to follow. Basically you download a backup file to your PC, load it on your BlackBerry, register your BlackBerry to get the other service books you need. This should get the needed service book on the BlackBerry and you would be good to go.
Good luck!

